Search

CN-121972017-A - Modified MABR (MABR) membrane material for inhibiting nitrite oxidizing bacteria

CN121972017ACN 121972017 ACN121972017 ACN 121972017ACN-121972017-A

Abstract

The application relates to the technical field of sewage treatment, in particular to a modified MABR membrane material for inhibiting nitrite oxidizing bacteria, which comprises a hollow fiber membrane matrix and a functional layer supported on the outer surface of the hollow fiber membrane matrix, wherein the functional layer comprises an iron-based active component and a carrier matrix, and the functional layer is combined with the hollow fiber membrane matrix in a chemical bonding or molecular embedding way. The membrane material can selectively inhibit the activity of nitrite oxidizing bacteria at the membrane-biomembrane interface by slowly releasing iron ions (Fe 2+ and Fe 3+ ) in the operation process, stabilize nitrite accumulation and promote the anaerobic ammonia oxidation denitrification process. Compared with the prior art, the application has the advantages of accurate and long-acting inhibition effect, high biological selectivity, firm structure, excellent mass transfer performance and the like, and provides a core material support for the engineering application of the MABR-Anamox process.

Inventors

  • LIU MENGMENG
  • CHEN YASONG
  • SUN WAN
  • Nie Zhonglin
  • PENG MENGWEN
  • WANG ZHIYONG
  • WU LEI

Assignees

  • 中国长江三峡集团有限公司

Dates

Publication Date
20260505
Application Date
20260331

Claims (10)

  1. 1. A modified MABR membrane material for inhibiting nitrite oxidizing bacteria, characterized in that the membrane material comprises a hollow fiber membrane matrix and a functional layer supported on the outer surface of the hollow fiber membrane matrix, wherein the functional layer comprises an iron-based active component and a carrier matrix and is used for selectively inhibiting nitrite oxidizing bacteria at a membrane-biological membrane interface, and the functional layer is combined with the hollow fiber membrane matrix through chemical bonding or molecular embedding; The functional layer has a thickness of 0.1-10 μm and is configured to release a total iron ion concentration of 0.1-10 μm at the membrane-biofilm interface.
  2. 2. The modified MABR film material according to claim 1, wherein the functional layer has a thickness of 0.5-5 μm; And/or, the iron ions include at least one of Fe 2+ or Fe 3+ .
  3. 3. The modified MABR membrane material of claim 1, wherein the material of the hollow fiber membrane matrix comprises at least one of polypropylene, polyvinylidene fluoride, polytetrafluoroethylene, polysulfone, polyethersulfone, or polydimethylsiloxane; and/or the hollow fiber membrane has an outer diameter of 0.5-3mm, a wall thickness of 0.2-1mm, and an average pore diameter of 0.01-1 μm.
  4. 4. The modified MABR film material of claim 1, wherein the iron-based active component comprises at least one of zero-valent iron nanoparticles and iron oxide; And/or the particle size of the iron-based active component is 10-200nm, and the iron-based active component accounts for 5-60 wt% of the total mass of the functional layer.
  5. 5. The modified MABR film material according to claim 4, wherein the iron oxide is at least one selected from the group consisting of ferroferric oxide, goethite and ferrihydrite; And/or the carrier matrix comprises at least one of silica sol-gel, polydopamine, chitosan, sodium alginate, polyethylenimine, polyvinyl alcohol or polyacrylic acid.
  6. 6. A method for producing a modified MABR membrane material for inhibiting nitrite oxidizing bacteria according to any one of claims 1 to 5, wherein the functional layer is supported on the outer surface of the hollow fiber membrane by an in-situ synthesis method or a blend spinning method.
  7. 7. The method for preparing a modified MABR membrane material according to claim 6, wherein the in situ synthesis method comprises the steps of: S11, performing surface activation pretreatment on the hollow fiber membrane matrix; S12, immersing the pretreated film matrix into a mixed solution containing an iron precursor and a carrier matrix precursor; s13, curing and post-treating the film loaded with the functional layer; the blend spinning method comprises the following steps: s21, mixing the iron-based nano particles, a membrane matrix polymer, a carrier matrix, a solvent and a pore-forming agent to form uniform casting solution; s22, extruding the film casting solution through a spinneret by adopting a dry-wet spinning process, and solidifying the film casting solution through phase inversion to form a film; S23, post-processing is carried out on the formed film.
  8. 8. The method for producing a modified MABR film material according to claim 7, wherein the method for surface activation pretreatment in the in situ synthesis method comprises at least one of chemical coupling method, vapor deposition method, plasma treatment method, photochemical treatment method; And/or, the iron precursor comprises at least one of ferrous sulfate or ferric chloride; And/or the carrier matrix precursor is ethyl orthosilicate, and the in-situ reaction is hydrolysis condensation reaction under the condition that the pH value is 8.0-10.0; And/or the carrier matrix precursor is dopamine hydrochloride, and the in-situ reaction is an oxidation self-polymerization reaction under the condition that the pH value is 8.0-9.0; And/or the carrier matrix in the blending spinning method is at least one selected from chitosan, sodium alginate, polyethyleneimine, polyvinyl alcohol or polyacrylic acid; And/or, in the in-situ synthesis method, immersing the pretreated film substrate into a mixed solution containing an iron precursor and a carrier substrate precursor for 1-60h; and/or controlling the thickness of the functional layer by regulating and controlling the addition amount of the iron-based nano particles in the blending spinning method, wherein the addition amount of the iron-based nano particles is 1-15% of the high molecular mass of the film matrix.
  9. 9. The method for preparing a modified MABR membrane material according to claim 8, wherein the membrane matrix polymer comprises at least one of polyvinylidene fluoride, polysulfone or polyethersulfone; And/or the solvent comprises N-methylpyrrolidone; And/or, the porogen comprises polyvinylpyrrolidone.
  10. 10. Use of the modified MABR membrane material for inhibiting nitrite oxidizing bacteria according to any one of claims 1 to 5 or the modified MABR membrane material obtained by the method for producing the modified MABR membrane material for inhibiting nitrite oxidizing bacteria according to any one of claims 6 to 9 in sewage treatment.

Description

Modified MABR (MABR) membrane material for inhibiting nitrite oxidizing bacteria Technical Field The application relates to the technical field of sewage treatment, in particular to a modified MABR membrane material for inhibiting nitrite oxidizing bacteria. Background The main stream sewage denitrification technology based on anaerobic ammonia oxidation (Anamox) is regarded as a revolutionary direction of next generation sewage treatment because of no need of organic carbon source, low sludge yield, low energy consumption and low carbon emission. Successful implementation of this technique relies on the stable, efficient provision of the reaction substrate nitrite (NO 2–). The membrane aeration biological membrane reactor (MABR) can spontaneously form a dissolved oxygen gradient in a single biological membrane by virtue of the unique characteristics of gas phase oxygen supply and reverse mass transfer, provides an ideal platform for enriching Ammonia Oxidizing Bacteria (AOB) and anaerobic ammonia oxidizing bacteria (AnAOB) under the main stream condition, and is one of key technologies for realizing main stream anaerobic ammonia oxidation. However, this technical path faces a fundamental challenge in the competition of nitrite oxidizing bacteria (Nitrite-Oxidizing Bacteria, NOB). NOB uses nitrite as a substrate, oxidizes the nitrite into nitrate, directly consumes nitrite required by Anamox reaction, competes with AOB for oxygen and competes with AnAOB for survival space. In the mainstream sewage environment with lower temperature and variable substrate concentration, NOB has difficult predicted proliferation potential, often causes instability of shortcut nitrification process and failure of nitrite accumulation, and finally causes the breakdown of the whole autotrophic denitrification system. The traditional NOB inhibition strategy, such as regulating and controlling dissolved oxygen, sludge age, temperature, pH or adding chemical inhibitors (such as hydroxylamine, chlorate and the like), has the problems of complex control, unstable effect, high running cost or ecological risk in the practical sewage plant application. In recent years, researches show that certain forms of iron (such as Fe 2+/Fe3+) have a selective inhibition effect on the metabolic activity of NOB, the mechanism of the iron can relate to interference of cytochrome c oxidase or nitrite oxidoreductase (NXR), and the prior art generally feeds soluble ferric salt into water in a homogeneous way, but the method has obvious defects that (1) iron ions are rapidly diffused and diluted in a reactor and are difficult to maintain effective concentration at a key biomembrane-membrane interface, (2) intermittent feeding causes concentration fluctuation, the inhibition effect is not continuous, (3) excessive iron ions can cause toxicity to other functional bacterial groups such as AnAOB, and cause increase of chromaticity of effluent and secondary pollution, and (4) the medicament consumption and the operation cost are increased. To overcome the above drawbacks, the prior art attempts to directly load iron-based materials onto membrane modules. For example, there is a study that discloses a membrane module based on Fe/C loading, in which an iron carbon powder layer is deposited on the surface of a hydrophobic organic membrane by vacuum filtration for enhancing in situ catabolic reduction of nitrate produced by anaerobic ammoxidation. The technology can relieve nitrate accumulation to a certain extent, but has the core purpose of 'terminal treatment' of nitrate instead of inhibiting proliferation of NOB from the source, and the powder layer formed by physical suction filtration has weak binding force and is easy to fall off under long-term hydraulic shearing, and simultaneously, additionally added thick layers can increase oxygen mass transfer resistance and influence the core oxygen supply efficiency of MABR. In addition, research discloses a preparation method of a nano-iron-loaded fiber membrane, which loads nano iron on a fiber mat through electrostatic spinning and is used for removing pollutants in water body through catalytic reduction. However, the fiber felt prepared by the technology is of a non-woven fabric structure, is not a hollow fiber membrane, is not suitable for a gas reverse mass transfer mode of an MABR reactor, and has a mechanism of action of chemical reduction, and does not involve selective biological inhibition of NOB. For a long time, the technical personnel generally consider that the oxygen mass transfer resistance is increased when the functional layer is loaded on the surface of the membrane, and the thicker the functional layer is, the more the loaded functional components are, and the better the inhibition effect is. Thus, the prior art tends to employ thicker functional layers without considering the possibility of ultra-thin functional layers to maintain excellent mass transfer properties while ensuring suppression e